Why is Isa (Jesus) called the messiah?

Isa(Jesus) is called the Messiah in the Quran in Surah Ali 'Imran 45 (3:45) , which directly translates to savior. However, if Islam rejects the idea that he saved the world from Sin as Christians believe, what is the purpose of this title at all? Some say that he was given this title because he came to show the jews the right path or because he was from God; however, if this is the case, then wouldn't that give every prophet the title of messiah? So why was Jesus the only one given that title? and what did he come to save us from if not sin? Also, if I may add, was he just a messiah to the Jews, or was it to the whole world?